title: Skin temperature over the carotid artery provides an accurate noninvasive estimation of core temperature in infants and young children during general anesthesia.
abstract: BACKGROUND
  The accurate measurement of core temperature is an essential aspect of intraoperative management in children. Invasive measurement sites are accurate but carry some health risks and cannot be used in certain patients. An accurate form of noninvasive thermometry is therefore needed. Our aim was to develop, and subsequently validate, separate models for estimating core temperature using different skin temperatures with an individualized correction factor.
  
  
  METHODS
  Forty-eight pediatric patients (0-36 months) undergoing elective surgery were separated into a modeling group (MG, n = 28) and validation group (VG, n = 20). Skin temperature was measured over the carotid artery (Tsk_carotid ), upper abdomen (Tsk_abd ), and axilla (Tsk_axilla ), while nasopharyngeal temperature (Tnaso ) was measured as a reference.
  
  
  RESULTS
  In the MG, derived models for estimating Tnaso were: Tsk_carotid  + 0.52; Tsk_abd  + (0.076[body mass] + 0.02); and Tsk_axilla  + (0.081[body mass]-0.66). After adjusting raw Tsk_carotid, Tsk_abd , and Tsk_axilla values in the independent VG using these models, the mean bias (Predicted Tnaso - Actual Tnaso [with 95% confidence intervals]) was +0.03[+0.53, -0.50]°C, -0.05[+1.02, -1.07]°C, and -0.06[+1.21, -1.28°C], respectively. The percentage of values within ±0.5°C of Tnaso was 93.2%, 75.4%, and 66.1% for Tsk_carotid, Tsk_abd , and Tsk_axilla , respectively. Sensitivity and specificity for detecting hypothermia (Tnaso  < 36.0°C) was 0.88 and 0.91 for Tsk_carotid , 0.61 and 0.76 for Tsk_abd , and 0.91 and 0.73 for Tsk_axilla . Goodness-of-fit (R(2) ) relative to the line-of-identity was 0.74 (Tsk_carotid ), 0.34 (Tsk_abd ), and 0.15 (Tsk_axilla ).
  
  
  CONCLUSIONS
  Skin temperature over the carotid artery, with a simple correction factor of +0.52°C, provides a viable noninvasive estimate of Tnaso in young children during elective surgery with a general anesthetic.
authors.affiliation: Faculty of Health Sciences, Thermal Ergonomics Laboratory, University of Ottawa, Ottawa, ON, Canada; Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.
authors.forename: Ollie
authors.initials: O
authors.lastname: Jay
authors.forename: Yannick
authors.initials: Y
authors.lastname: Molgat-Seon
authors.forename: Shirley
authors.initials: S
authors.lastname: Chou
authors.forename: Kimmo
authors.initials: K
authors.lastname: Murto
mesh_terms: D000005:Abdomen / Q000502:physiology; D000465:Algorithms; D000768:Anesthesia, General / Q000379:methods*; D001365:Axilla / Q000502:physiology; D001831:Body Temperature / Q000502:physiology*; D002339:Carotid Arteries / Q000502:physiology*; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007035:Hypothermia / Q000175:diagnosis; D007223:Infant; D008297:Male; D015233:Models, Statistical; D011229:Preanesthetic Medication; D015203:Reproducibility of Results; D012881:Skin Temperature / Q000502:physiology*; D062125:Thermometry
keywords: body temperature; intraoperative thermometry; measurement sites; pediatric thermal management; thermoregulation